Harnessing cooling energy
Efficient carbonation with EcoVap
The beverage industry is increasingly using gases that are delivered in liquid form and vaporised for a specific application. The EcoVap process makes the cooling energy that is released available for other applications. This allows energy to be saved and the carbon footprint to be reduced in cooling units, for example.
Beverage processing and bottling involves the use of various gases, which are mostly supplied in liquefied form in vacuum-insulated tanks. Liquid carbon dioxide (CO2) is particularly important here. It has to be returned to its gaseous state for the purpose of beverage carbonation. This is done by means of air vaporisers or electrically heated vaporisers. However, this process step does not make use of the cooling energy contained in the gas.
The process principle: cold extraction in the heat exchanger
Integrated into the cooling system’s cooling circuit, the heat exchanger forms the centrepiece of the EcoVap process. Both the cryogenic liquefied gas and the cooling system’s heat transfer medium (e.g. cooling water or brine) flow through the unit. The heat transfer process involves the "exchange" of heat for cold.
The construction consists of a special tube bundle heat exchanger. The facility’s special design ensures that, despite the extremely low temperatures of the liquid gas, the temperature of the heat transfer medium does not drop below freezing point as it flows through the unit. As the liquid gas vaporises during its passage through the EcoVap system, it extracts a considerable amount of energy from the coolant, significantly lowering its temperature. The coolant is conducted from the cooling circuit’s return line into the EcoVap unit, where, for the most part, it passes the heat exchanger jacket and is thus cooled. It then flows to the refrigerating machine – as before without EcoVap –, where its temperature can be further regulated as required. After this process, the refrigerating machine requires significantly less electrical energy to achieve the desired cooling effect thanks to the reduced input temperature.
Electric vaporisers unnecessary in winter
At the EcoVap system’s outlet, the gas, which was liquid before, has completely vaporised. The gas temperature mainly depends on the temperature of the heat transfer medium. In contrast to air vaporisers, EcoVap is not dependent on weather conditions. As a rule, no condensation forms on the pipes either.
Another advantage of EcoVap is the reduced requirement for electric heating to vaporise the liquid gas. Especially in the winter months, air vaporisers are often not enough on their own to supply the liquid gas with the heat required for vaporisation since the temperature difference between the ambient air and the gas is too small. In this case, it is necessary to use electrically heated vaporisers. When using EcoVap, these are only required as a potential back-up, plus they do not use any electricity in normal operation.
Cutting costs: a real-life example
By installing the EcoVap process, a beverage producer was able to save around 560,000 kWh a year for vaporisation and heating of 2,500 kg of CO2/h and simultaneous cooling of process water. The investment paid for itself after just two years.
The EcoVap principle can be used not only for carbonation in beverage production but in any industrial application that involves the vaporisation of liquid gas with a simultaneous requirement for process cooling. Further possible applications include the wastewater neutralisation with CO2 the CO2 greenhouse fertilising.
Box: Carbonation in the beverage industry
Soft drinks generally contain 5 to 9 g of CO2/l. If required, wine is carbonated with about 2.5 g of CO2/l. The gas produces the characteristic feel of freshness (sparkle) and improves the biological shelf life of beverages. The carbonation process requires carbon dioxide in its gaseous state. Generally speaking, the process of dissolving gases in liquids depends on the composition of the liquid, the temperature, the pressure, the exchange surface and the dwell time. A cooling circuit ensures optimal temperatures. Thanks to EcoVap, you can make a double saving: firstly, there is no need for an electric vaporiser for the gas, and secondly, there is a reduced load on the refrigerating machine.